Vehicles (e.g., automobiles, tractors and excavators) often include electrical applications (e.g., electric drives). A dc bus voltage may be regulated by controlling a generator. Typically the generator is driven by a diesel engine running at a constant speed. The established dc bus voltage may then provide electric power to many motoring applications on the vehicle.
Typically the diesel engine and the generator each have an associated controller. The generator controller receives a control signal (e.g., a torque control signal) to indicate a manner by which the controller should be controlling the generator. For example, the control signal may indicate a steady-state, an increased demand or a decreased demand. The diesel engine controller maintains a shaft speed of the generator. In this way the generator maintain a desired dc bus voltage.
Further, if the electrical motor is configured as a drive motor (e.g., a traction motor) the motor may also operate to charge the vehicle dc bus during a vehicle regenerative braking period. Regenerative braking is an energy recovery mechanism which slows the vehicle 100 down by converting the vehicle's 100 kinetic energy into another form (e.g., electric energy), which can be either dissipated immediately across crow bar resistor or stored until needed. The energy recovered may be used to maintain a desired dc bus voltage as well.